The present invention relates to fixing toner images such as are produced by electrophotographic and other electrostatic processes. More particularly, the present invention is directed to solvent vapor fixing of toner images, wherein the toner image is placed in close juxtaposition to an absorbent web having a volatile liquid solvent absorbed thereon, and the toner image is fixed upon a substrate by the action of the solvent vapors emanating from said web.
In one conventional electrophotographic process, a photoconductive electrically insulating layer backed with an electrical conducting substrate is uniformly electrostatically pre-charged by any suitable means, such as by corona discharge, and then is exposed to a light image to form an electrostatic latent image. The electrostatic latent image is converted to a visible image by causing fine toner particles to adhere electrostatically to the latent image in accordance with the charge pattern. The toner image thus formed may then be transferred to and fixed upon a transfer sheet, or it may be fixed directly on the photoresponsive layer. In another electrostatic process, the toner images are obtained through a substantially similar process, except that the formation of the electrostatic latent image is effected through such means as corona discharge from selective or patterned electrodes to a dielectric sheet or web.
According to the present invention, the toner image is fixed to a substrate by being placed in closely spaced juxtaposition to a porous absorbent web having a volatile liquid toner solvent absorbed thereon. Suitable solvents for this purpose for use with most commercial toners are the non-combustible chlorinated hydrocarbons. The vapors of said solvent soften the toner particles and thereby cause the toner image to become affixed to its substrate. Because the toner image is held in close proximity to the fixing solvent absorbed on the web, the toner image is subjected to a high concentration of fixing agent vapor, thereby causing the image to be fixed in a very short period of time. The present invention also makes effective use of housing means for the solvent laden web prior to, after and/or during the fixing operation, thereby minimizing or substantially eliminating the dispersion of the solvent vapor into the environs, and avoiding the health hazards attendant the inhalation of most solvent vapors.
It is therefore one object of the present invention to provide for fixing toner images by placing the toner image in closely spaced proximity to an absorbent web having a volatile liquid toner solvent absorbed thereon, whereby the toner image is fixed by the solvent vapors emanating from said web.
A further object of the present invention is to provide for such solvent vapor fixing a toner image, while containing said web within a housing to minimize dispersion of solvent vapor into the environs.
Still another object of the present invention is to provide for such solvent vapor fixing of toner images either intermittently or continuously over an extended and indefinite period of time.
Other objects and advantages of the present invention will become apparent from the detailed description given hereinafter. It is understood, however, that the detailed description and specific examples, while indicating preferred embodiments of the invention, are presented for illustration only, and various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art.